How do I make a plan?


Any experienced (and good) blitz player will not only have strategic plans throughout, but also good technique, endgame play, etc.

I've been 2100 blitz here. I always had a plan (even if just a superficial one) in blitz games. I never met a guy rated 2000 that moves randomly.
At that point recognizing general plans is so ingrained that it happens automatically. Sure, maybe you could find some tactical genius that has no concept of strategy and a blitz rating at (or over) 2000, but I'd guess >99% of players over 2000 have had plenty of experience in longer time controls, read chess books, practiced openings and technical endgames, etc.
Probably most people rated over 1500 too.
When you beat a low rated player it's easy to point to some tactic they missed, but IMO tactical mistakes happen when the opponent is pushed to their limits strategically. Even GMs in slow games will miss relatively simple tactics in complex positions for this reason.
But sure, at a certain rating blunders just happen because people don't pay attention. Maybe you could get to 1000 or 1200 or something just by paying attention, but not 2000, not if we're being honest.

Some people specialize in the positions they play all day, so sure, get them out of their comfort zone and they fall apart. I'd call them overrated, but not clueless.
Almost 100% of my thought during blitz is just focused on small improvements for my pieces... but it depends what you mean by "superficial." There are plenty of learned ideas used without needing to think about it. They're superficial in the sense that it's done quickly, but they're good enough plans for any OTB game. It would be hard to show you a blitz game of mine that doesn't involve this.
As a simple example a maroczy or IQP structure I'm going to know many standard maneuvers and evaluations that can stretch into the endgame. A well known one is that heavy piece endgames are unfavorable to the IQP holder.
You could even argue that in OTB tournament games strategic planning is superficial... we usually already know our strategic aims, and we only spend time trying to find the most efficient or error free way to execute them.

Maybe it's easy to think strategically when playing weaker players, but FWIW here is a 3 minute game.
Comments are not post game analysis, they're my in-game thoughts.

Unless a game is nearly pure tactics (King's Gambit, Budapest Defense, etc.) plans are necessary, especially in the middlegame and endgame. Many authors claim that lack of a plan is one of the most common problems of beginners.
To make a plan I believe it is necessary to first evaluate the position, at least for a *good* plan. There are books on that, and there is a relatively complete, finite list of things to look for. Each opening has a set of plans that go with it, so if you know an opening and its plans, it's much easier to decide if a standard plan is a good one for your particular position.
For example, if an opponent has an isolated queen's pawn (IQP), a good plan is to blockade it, then pile on the pressure against against it, threatening to win it. If both players castle on opposite sides (common in the Najdorf and Dragon Sicilians) then the most common plan is a flank attack against the castled king. If you have a pawn majority on one side (as in the Exchange Ruy Lopez) then the main plan is to get a passed pawn on that flank, then promote it. If one player has delayed castling too long in an open game, say by making too many pawn moves, then a good plan is usually to open up the center before the king can castle, often by sacrificing a pawn. And so on. First the assessment is made, then the plan, then the moves.